One Strong Convincing Argument

I am trying to convince my End User who also happens to be VP of Data Analysis that when we build a cube it is better to split it up if we have 35 Dimensions instead of putting them all into one. This cube will have 5 Measures. I have recommended it to be split into three.

What is one Strong Convincing Argument(or more than one) that I can use.

I have already told him if is a Maintenance NIGHTMARE, Loading of the Fact Table would be a NightMare.
I have shown his articles which say that it is a Big Mistake to have more than 10 dimensions.

But he keeps on insisting that let us try it out before we run into problems. He says let us add one by one and see how far we can go? Ofcourse he wants to be able to play with all numbers side by side.

For all that matters, the Cube will probably build up and even get processed and after which he will say -- hey we got it, there is no need to split it up.

I do it find it hard to Optimize the Cubes even at 10%. But when we Process it at 0% Optimization there seems to be no problem what so ever for him to access via MS Excel, so he insists that we can Process it at 0% OPtimization.